Metagenomic sequencing of bacterial communities in Baijiu pit mud
Gas-fermenting clostridia are attractive biocatalysts for sustainable bioproduction, converting CO and CO2 into ethanol, acetate, and other chemicals via anaerobic fermentation. Although a few strains have been successfully industrialized, the continued discovery of new strains with desirable metabolic traits remains critical for advancing the field. In this study, we targeted anaerobic microbial communities from Baijiu fermentation pit mud, using a mixed sugar-syngas carbon source coupled with a gradient sugar-reduction strategy, selectively enriched and isolated multiple Clostridium autoethanogenum strains capable of autotrophic growth and product synthesis from CO/CO2. The newly isolated strains showed distinct genomic and phenotypic differences. The optimal isolate, LG-6, outperformed the reference strain DSM 10061, showing 72% and 27% improvements in biomass and ethanol yield, respectively, in batch gas fermentation. Under continuous gas supply, LG-6 reached an OD600 of 16.9, produced 21.5 g/L ethanol at a rate of 0.2 g/L/h, and accumulated no acetate as a byproduct. Moreover, upon engineering with heterologous pathways, LG-6 produced 2.49-fold and 2.45-fold higher acetone and 3-hydroxybutyrate than DSM 10061 in gas fermentation. Our findings unveil Baijiu pit mud as a promising source of gas-fermenting clostridia, providing new opportunities for obtaining high-performance strains for industrial applications.
host
environmental sample
isolation_source
Baijiu fermentation pit mud
collection_date
2022-09-30
geo_loc_name
China: Sichuan and Anhui provinces
lat_lon
not collected
BioSampleModel
Metagenome or environmental